DMH-induced rat colon cancer is being explored as a model of human colorectal cancer. Additional data have been gathered demonstrating the protective effect dietary fiber exerts on the induction pattern of these tumors. While gut transit time/stool bulk appear to be important variables, current studies are being extended to examine the role of microflora and bile salts/acids in this system. Experiments are in progress to identify, isolate, and develop a radioimmunoassay for a CEA-like marker in this system. Ouchterlony immunodiffusion analysis has demonstrated such a tumor-specific factor. Intralesional BCG-CW therapy is being compared to surgical resection in the treatment of primary colon tumors.